Spacecraft.ShadowTimes(Variable, Array, Array) Method

Description

Determines the entry time, exit time, and duration of a Spacecraft's pass through the shadow of a CelestialObject specified by celestialObjectID.

The shadow times are determined using a conical shadow. The algorithm to determine the times a Spacecraft is in any portion of the occulting body is shown in the diagram below.

Algorithm used to determine if a Spacecraft is in the occulting body's shadow.

Note: This method uses a spherical model for the occulting body. Use the options available in the VisibilityCalculator to exercise more control over the analysis.

Timing Precision Mode

This page describes functionality in millisecond timing precision mode. Millisecond timing precision mode is deprecated and will be removed in a future release. We recommend that you migrate your Mission Plans to nanosecond timing precision mode.

Click here to see the documentation for this object in nanosecond timing precision mode.

Note: This is an interval method. See the Interval Methods page for more information.

Note: This method has a state. See the Methods and Properties with State page for more information.

Method Signature

Spacecraft.ShadowTimes(	Variable celestialObjectID,
	Array EventTime,
	Array EventType)

Arguments

celestialObjectID

Description:

ID of the CelestialObject to use as the occulting body. Body ID's 1-11 are assigned to the default Solar System objects, as shown below. Custom CelestialObjects will have body ID's starting at 12 and assigned in the order they are created.

Valid Values:

Celestial Object	Value
Mercury	Mercury.BodyID or 1
Venus	Venus.BodyID or 2
Earth	Earth.BodyID or 3
Mars	Mars.BodyID or 4
Jupiter	Jupiter.BodyID or 5
Saturn	Saturn.BodyID or 6
Uranus	Uranus.BodyID or 7
Neptune	Neptune.BodyID or 8
Pluto	Pluto.BodyID or 9
Moon	Moon.BodyID or 10
Sun	Sun.BodyID or 11
<Custom CelestialBody>	<Custom CelestialBody>.BodyID, starting at 12 and assigned in the order the custom CelestialObjects are created.

EventTime

Description:

The time that the event occurred.

The FF_Preferences.IntervalEventReportingBehavior property controls whether the start of propagation is reported as an event. By default, if the time in shadow starts before the beginning of the propagation span, FreeFlyer will label the start of the propagation as the start of the time in shadow.

EventType
Description:	The type of the event that occurred. Event type == 1 is entry into annular shadow. Event type == 2 is exit from annular shadow. Event type == 101 is entry into umbral shadow. Event type == 102 is exit from umbral shadow. Event type == 201 is entry into penumbral shadow. Event type == 202 is exit from penumbral shadow.

Return Value

Type:

number

Returns the number of elements filled into EventType and EventTime arrays.

Syntax

myVariable1 = mySpacecraft1.ShadowTimes(myVariable2, myArray1, myArray2);